//  DistanceNode.java
//
//  Author:
//       Antonio J. Nebro <antonio@lcc.uma.es>
//       Juan J. Durillo <durillo@lcc.uma.es>
//
//  Copyright (c) 2011 Antonio J. Nebro, Juan J. Durillo
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
// 
//  You should have received a copy of the GNU Lesser General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
package etmo.util;

/**
 * This is an auxiliar class for calculating the SPEA2 environmental selection.
 * Each instance of DistanceNode contains two parameter called
 * <code>reference_</code> and <code>distance_</code>. <code>reference_</code>
 * indicates one <code>Solution</code> in a <code>SolutionSet</code> and
 * <code>distance_</code> represents the distance_ to this solution.
 */
public class DistanceNode {

	/**
	 * Indicates the position of a <code>Solution</code> in a
	 * <code>SolutionSet</code>.
	 */
	private int reference_;

	/**
	 * Indicates the distance to the <code>Solution</code> represented by
	 * <code>reference_</code>.
	 */
	private double distance_;

	/**
	 * Constructor.
	 * 
	 * @param distance
	 *            The distance to a <code>Solution</code>.
	 * @param reference
	 *            The position of the <code>Solution</code>.
	 */
	public DistanceNode(double distance, int reference) {
		distance_ = distance;
		reference_ = reference;
	} // DistanceNode

	/**
	 * Sets the distance to a <code>Solution</code>
	 * 
	 * @param distance
	 *            The distance
	 */
	public void setDistance(double distance) {
		distance_ = distance;
	} // setDistance

	/**
	 * Sets the reference to a <code>Solution</code>
	 * 
	 * @param reference
	 *            The reference
	 */
	public void setReferece(int reference) {
		reference_ = reference;
	} // setReference

	/**
	 * Gets the distance
	 * 
	 * @return the distance
	 */
	public double getDistance() {
		return distance_;
	} // getDistance

	/**
	 * Gets the reference
	 * 
	 * @return the reference
	 */
	public int getReference() {
		return reference_;
	} // getReference
} // DistanceNode
